Aug 1, 1976

pH, temperature, humidity and the dynamic force-area curve of dipalmitoyl lecithin

Respiration Physiology
G ColaciccoE M Scarpelli


Both high pH at 25 degrees C and humidity at 37 degrees C prevent DPL films from attaining zero surface tension, whereas humidity at 25 degrees C and high pH at 37 degrees C do not. At 37 degrees C DPL lowered surface tension to zero when spread from organic solvent or when absorbed from aqueous 0.15 M NaCl in the surface balance in which the surface film was exposed to the room air (dry film). Upon saturation of the atmosphere with water vapor in equilibrium with the aqueous phase at 37 degrees C in a closed chamber, DPL lost the ability to produce zero surface tension, and the gamma min of the DPL film increased from zero to 22 dyne/cm. Addition of DPL in chloroform to distilled water before dispersion by sonication did not prevent the effect of the humidity. However, when the chloroform solution of DPL was added to 0.15 M NaCl before sonication, the adsorbed film produced immediately a stable gamma min of zero in a saturated atmosphere, 37 degrees C. In the absence of chloroform, with DPL adsorbed from either distilled water or 0.15 M NaCl, the effect of humidity was reversed either by removing the chamber and returning the wet film to room air or by introducing small quantities of dispersing agents such as cholesteryl palmi...Continue Reading

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Mentioned in this Paper

Interfacial Force
Lecithinum, lecithin, Homeopathic preparation
Distilled water
Pulmonary Surfactants
Dyne veterinary drug
Organic solvent product

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